Resveratrol attenuates lipopolysaccharide-induced acute kidney injury by suppressing inflammation driven by macrophages

Effects of resveratrol on alpha-amanitin-induced nephrotoxicity in BALB/c mice

Alpha-amanitin (α-AMA), the primary toxin of Amanita phalloides, is known to cause nephrotoxicity and hepatotoxicity. Resveratrol is an antioxidant that has shown efficacy in many nephrotoxicity models. The aim of this study was to investigate the effects of resveratrol against the early and late stages of α-AMA-induced nephrotoxicity, compared to those of silibinin, a well-known antidote for poisoning by α-AMA-containing mushrooms. Mice kidney tissues were obtained from five groups: (1) α-AMA + NS (simultaneous administration of α-AMA and normal saline), (2) α-AMA + SR (simultaneous administration of α-AMA and resveratrol), (3) α-AMA + 12R (resveratrol administration 12 h after α-AMA administration), (4) α-AMA + 24R (resveratrol administration 24 h after α-AMA administration), and (5) α-AMA + Sil (simultaneous administration of α-AMA and silibinin). Histomorphological and biochemical analyses were performed to evaluate kidney damage and oxidant-antioxidant status in the kidney. Scores of renal histomorphological damage decreased significantly in the early resveratrol treatment groups (α-AMA + SR and α-AMA + 12R), compared to those in the α-AMA + NS group (p < 0.05). Catalase levels increased significantly in the α-AMA + SR group, compared to those in the α-AMA + NS group (p < 0.001). Early resveratrol administration within 12 h after α-AMA ingestion may reverse the effects of α-AMA-induced nephrotoxicity, partly through its antioxidant action, thereby suggesting its potential as a treatment for poisoning by α-AMA-containing mushrooms.

Application of Herbal Traditional Chinese Medicine in the Treatment of Acute Kidney Injury

Acute kidney injury (AKI) is a clinical syndrome characterized by a rapid loss of renal function, which may further develop into chronic kidney damage (CKD) or even end-stage renal disease (ESRD). AKI is a global health problem associated with high morbidity and costly treatments, and there is no specific or effective strategy to treat AKI. In recent years, Traditional Chinese Medicine (TCM) has attracted more attention, with lines of evidence showing that application of TCM improved AKI, and the mechanisms of action for some TCMs have been well illustrated. However, reviews summarizing the progress in this field are still lacking. In this paper, we reviewed TCM preparations and TCM monomers in the treatment of AKI over the last 10 years, describing their renal protective effects and mechanisms of action, including alleviating inflammation, programmed cell death, necrosis, and reactive oxygen species. By focusing on the mechanisms of TCMs to improve renal function, we provide effective complementary evidence to promote the development of TCMs to treat AKI. Moreover, we also summarized TCMs with nephrotoxicity, which provides a more comprehensive understanding of TCMs in the treatment of AKI. This review may provide a theoretical basis for the clinical application of TCMs in the future.

Resveratrol Attenuates Allergic Asthma and Associated Inflammation in the Lungs Through Regulation of miRNA-34a That Targets FoxP3 in Mice

Asthma is a chronic inflammatory disease of airways mediated by T-helper 2 (Th2) cells involving complex signaling pathways. Although resveratrol has previously been shown to attenuate allergic asthma, the role of miRNA in this process has not been studied. We investigated the effect of resveratrol on ovalbumin-induced experimental allergic asthma in mice. To that end, BALB/c mice were immunized with ovalbumin (OVA) intraperitoneally followed by oral gavage of vehicle (OVA-veh) or resveratrol (100 mg/kg body) (OVA-res). On day 7, the experimental groups received intranasal challenge of OVA followed by 7 days of additional oral gavage of vehicle or resveratrol. At day 15, all mice were euthanized and bronchioalveolar fluid (BALF), serum and lung infiltrating cells were collected and analyzed. The data showed that resveratrol significantly reduced IL-5, IL-13, and TGF-β in the serum and BALF in mice with OVA-induced asthma. Also, we saw a decrease in CD3+CD4+, CD3+CD8+, and CD4+IL-4+ cells with increase in CD4+CD25+FOXP3+ cells in pulmonary inflammatory cell infiltrate in OVA-res group when compared to OVA-veh. miRNA expression arrays using lung infiltrating cells showed that resveratrol caused significant alterations in miRNA expression, specifically downregulating the expression of miR-34a. Additionally, miR-34a was found to target FOXP3, as evidenced by enhanced expression of FOXP3 in the lung tissue. Also, transfection studies showed that miR-34a inhibitor upregulated FOXP3 expression while miR-34a-mimic downregulated FOXP3 expression. The current study suggests that resveratrol attenuates allergic asthma by downregulating miR-34a that induces increased expression of FOXP3, a master regulator of Treg development and functions.

Systematic review and meta-analysis of the protective effect of resveratrol on multiple organ injury induced by sepsis in animal models

Sepsis may directly lead to multiple organ failure, which is among the leading causes of mortality in critically ill patients. According to data released by the Global Sepsis Alliance, the number of mortalities due to sepsis exceeded the combined number for prostate cancer, breast cancer and AIDS in 2012. To date, studies have reported that resveratrol has marked positive effects including anti-inflammatory, anti-oxidative and pro-microcirculatory functions in sepsis-induced organ injury, significantly improving the survival time and mortality of sepsis animals. The present systematic review sought to further clarify the efficacy and safety of resveratrol in the treatment of sepsis. Studies on resveratrol application in the treatment of sepsis-induced organ injury in animal models were reviewed by searching various Chinese and other language databases (PubMed, Embase, CNKI, WanFang and WeiPu) and by manually searching the references of related articles. The selection and evaluation of the studies was performed by two independent reviewers. A total of 260 related studies were initially identified. Following application of the exclusion factors and inclusion criteria, 11 studies were included. Meta-analysis revealed that resveratrol exerted significant protective effect in sepsis-induced animal models of organ injury, through anti-inflammatory, anti-oxidant and pro-microcirculatory functions compared with in the placebo group. While nuclear factor κB (NF-κB) and nuclear factor E2-related factor 2 (NRF-2) are the two major signaling pathways to have been associated with the anti-inflammatory and anti-oxidative effects of resveratrol, these factors were not quantified for mean values, therefore not suitable for systematic evaluation. For related factors, the results of meta-analysis were as follows: For tumor necrosis factor-α (TNF-α), the standardized mean difference (SMD) was -13.50 [95% confidence interval (CI): -22.08, -4.91; P=0.002]; for malondialdehyde (MDA), the SMD was -3.10 (95% CI: -5.27, -0.93; P=0.005); for mean arterial pressure the SMD was 1.34 (95% CI: 0.07, 2.62; P=0.04); for interleukin (IL)-6 the SMD was -9.57 (95% CI: -20.90, 1.75; P=0.10); and for IL-10 the SMD was 0.80 (95% CI: -0.73, 2.34; P=0.31). It was concluded that resveratrol exerted significant anti-inflammatory and anti-oxidative effects through NF-κB and NRF-2 signaling pathways in animal models of sepsis-induced multiple organ injury, manifesting as significant downregulation of TNF-α and MDA expression and improved microcirculation, therefore ameliorating septic damage to the body, which may ultimately improve survival ratios.

Resveratrol improves human umbilical cord-derived mesenchymal stem cells repair for cisplatin-induced acute kidney injury

Human umbilical cord-derived mesenchymal stem cells (hucMSCs) are a promising tool for damaged tissues repair, especially for the kidney. However, their efficacy requires improvement. In order to optimize the clinical utility of hucMSCs, we adopted a strategy of treating hucMSCs with 20 μmol/L of resveratrol (Res-hucMSCs), applying it in a cisplatin-induced acute kidney injury model. Interestingly, we found that Res-hucMSCs exhibited a more efficient repairing effect than did hucMSCs. Resveratrol-promoted hucMSCs secreted platelet-derived growth factor-DD (PDGF-DD) into renal tubular cells resulting in downstream phosphorylation of extracellular signal-regulated kinase (ERK), which inhibited renal tubular cells apoptosis. In contrast, PDGF-DD knockdown impaired the renal protection of Res-hucMSCs. In addition, angiogenesis induced by PDGF-DD in endothelial cells was also involved in the renal protection of Res-hucMSCs. The conditioned medium of Res-hucMSCs accelerated proliferation and migration of vascular endothelial cells in vitro and CD31 was in a high-level expression in Res-hucMSCs group in vivo. Nevertheless, the angiogenesis was abrogated when Res-hucMSCs were treated with PDGF-DD siRNA. In conclusion, our findings showed that resveratrol-modified hucMSCs activated ERK pathway in renal tubular cells and promoted angiogenesis in endothelial cells via paracrine PDGF-DD, which could be a novel strategy for enhancing the therapy efficacy of hucMSCs in cisplatin-induced kidney injury.

Virgin olive oil and its phenol fraction modulate monocyte/macrophage functionality: a potential therapeutic strategy in the treatment of systemic lupus erythematosus

Monocytes and macrophages are critical effectors and regulators of inflammation and innate immune response, which appear altered in different autoimmune diseases such as systemic lupus erythematosus (SLE). Recent studies suggested that virgin olive oil (VOO) and particularly its phenol compounds might possess preventive effects on different immune-inflammatory diseases, including SLE. Here, we evaluated the effects of VOO (and sunflower oil) on lipopolysaccharide (LPS)-activated peritoneal macrophages from a model of pristane-induced SLE in BALB/c mice, as well as those of the phenol fraction (PF) from VOO on the immune-inflammatory activity and plasticity in monocytes and monocyte-derived macrophages from healthy volunteers. The release of nitrite and inflammatory cytokines was lower in LPS-treated peritoneal macrophages from pristane-SLE mice fed the VOO diet when compared with the sunflower oil diet. PF from VOO similarly decreased the secretion of nitrite and inflammatory cytokines and expression of inducible nitric oxide, PPARγ and Toll-like receptor 4 in LPS-treated human monocytes. PF from VOO also prevented the deregulation of human monocyte subset distribution by LPS and blocked the genetic signature of M1 macrophages while favouring the phenotype of M2 macrophages upon canonical polarisation of naïve human macrophages. For the first time, our study provides several lines of in vivo and in vitro evidence that VOO and PF from VOO target and counteract inflammatory pathways in the monocyte–macrophage lineage of mice with pristane-induced SLE and of healthy subjects, which is a meaningful foundation for further development and application in preclinical and clinical use of PF from VOO in patients with SLE.

Resveratrol ameliorates sepsis-induced acute kidney injury in a pediatric rat model via Nrf2 signaling pathway

Acute kidney injury (AKI) is a hyper-inflammation-induced abrupt loss of kidney function and has become a major public health problem. The cecal ligation and puncture (CLP) model of peritonitis in rat pups mimics the development of sepsis-induced pediatric AKI is pre-renal without morphological changes of the kidneys and high lethality. Resveratrol, a natural polyphenolic compound with low toxicity, has obvious anti-oxidant and anti-inflammatory properties. The present study aimed to determine whether resveratrol alleviates pediatric AKI and investigated the potential mechanism. Thus, a CLP model of 17-18 day-old rat pups was used to mimic the development of sepsis-induced AKI in children. In the group treated with resveratrol, renal injury induced by CLP was alleviated with downregulation of tumor necrosis factor (TNF)-α, interleukin (IL)-1β and kidney injury molecule (KIM)-1 expression. Nuclear factor-erythroid-2-related factor 2 (Nrf2) signaling is known to effectively inhibit inflammation, the present study found that resveratrol reduced the lipopolysaccharide-induced inflammatory response in kidney cells in vitro and induced the activation of Nrf2 signaling, including accumulation of nuclear Nrf2 and increase of the expression of Nrf2 target genes heme oxygenase (HO)-1 and NAD(P)H dehydrogenase (quinone) 1 (NQO1); this was confirmed by the induction of the expression of HO-1 and NQO1 by treatment of resveratrol in vitro and in vivo. Of note, knockdown of Nrf2 effectively abrogated the downregulation of TNF-α, IL-1β and KIM-1 expression induced by resveratrol in vitro. These results suggested that resveratrol ameliorates sepsis-induced acute kidney injury in a pediatric model of AKI via the Nrf2 signaling pathway.

Rationale for assessing the therapeutic potential of resveratrol in hematological malignancies

Promising results from pre-clinical studies on the naturally-occurring polyphenol resveratrol have generated considerable interest and somewhat excessive expectations regarding the therapeutic potential of this compound for treating or preventing various diseases, including cardiovascular and neurodegenerative disorders and cancer. Resveratrol has potent inhibitory activity in vitro against various tumor types, including cell lines derived from virtually all blood malignancies. Pharmacological studies have shown that resveratrol is safe for humans but has poor bioavailability, due to its extensive hepatic metabolism. Curiously, a substantial proportion of the orally administered resveratrol can reach the bone marrow compartment. Notably, various pathways dysregulated in blood cancers are known to be molecular targets of resveratrol, thus substantiating the potential utility of this agent in blood malignancies. In this review, we primarily focus on the scientific evidence that supports the potential utility of resveratrol for the management of select hematological malignancies. In addition, potential clinical trials with resveratrol are suggested.

Rutin, a quercetin glycoside, alleviates acute endotoxemic kidney injury in C57BL/6 mice via suppression of inflammation and up-regulation of antioxidants and SIRT1

Acute kidney injury (AKI) is a common complication following severe sepsis, its incidence is increasing, and it is associated with a high rate of morbidity and mortality. Rutin is a glycoside of the bioflavonoid quercetin with various protective effects due to its antioxidant and anti-inflammatory potential. In this research, we tried to assess the protective effect of rutin administration in a model of AKI in C57BL/6 mice. For induction of AKI, lipopolysaccharide (LPS) was injected once (10 mg/kg, i.p.) and rutin was p.o. given at doses of 50 or 200 mg/kg. Treatment of LPS-challenged group with rutin lowered serum level of creatinine and blood urea nitrogen (BUN), restored to some extent renal oxidative stress-related indices such as malondialdehyde (MDA), glutathione (GSH), and activity of superoxide dismutase (SOD) and catalase. In addition, rutin brought back renal nuclear factor-kappaB (NF-κB), toll-like receptor 4 (TLR4), cyclooxygenase-2 (COX2), sirtuin 1 (SIRT1), tumor necrosis factor α (TNFα), interleukin-6, and caspase 3 activity to their control levels. Moreover, protective effect of rutin was in accordance to a dose-dependent manner. Collectively, rutin is capable to mitigate LPS-induced AKI via appropriate modulation of renal oxidative stress, inflammation, and apoptosis.

Simultaneous purification of dihydrotanshinone, tanshinone I, cryptotanshinone, and tanshinone IIA from Salvia miltiorrhiza and their anti-inflammatory activities investigation

Dihydrotanshinone, tanshinone I, cryptotanshinone, and tanshinone IIA are major lipid-soluble constituents isolated from Salvia miltiorrhiza Bunge (Danshen). In the present study, a systematic method was developed to simultaneously isolate and purify those compounds using macroporous adsorption resins and semi-preparative HPLC with a dynamic axial compress (DAC) system. The Danshen extract (95% alcohol) was divided into three fractions using different concentrations of alcohol (0%, 45%, and 90%) on D101 column. The content of total tanshinones of 90% alcohol eluent (TTS) was over 97%. Furthermore, the anti-inflammatory effects of those samples were investigated on LPS-stimulated RAW264.7 cells and three animal models. The results showed that the anti-inflammatory effect of TTS in vitro was superior to the one of any other sample including 0% and 45% eluent, and total tanshinones capsules. In addition, TTS exhibited a stronger anti-inflammatory effect than that of dihydrotanshinone, tanshinone IIA, cryptotanshinone, and tanshinone I, respectively. For animal models, TTS could significantly suppress xylene-induced ear oedema and rescue LPS-induced septic death and acute kidney injury in mice. In summary, the separation process developed in the study was high-efficiency, economic, and low-contamination, which was fit to industrial producing. TTS is a potential agent for the treatment of inflammatory diseases.

Simultaneous purification of dihydrotanshinone, tanshinone I, cryptotanshinone, and tanshinone IIA from Salvia miltiorrhiza and their anti-inflammatory activities investigation

Dihydrotanshinone, tanshinone I, cryptotanshinone, and tanshinone IIA are major lipid-soluble constituents isolated from Salvia miltiorrhiza Bunge (Danshen). In the present study, a systematic method was developed to simultaneously isolate and purify those compounds using macroporous adsorption resins and semi-preparative HPLC with a dynamic axial compress (DAC) system. The Danshen extract (95% alcohol) was divided into three fractions using different concentrations of alcohol (0%, 45%, and 90%) on D101 column. The content of total tanshinones of 90% alcohol eluent (TTS) was over 97%. Furthermore, the anti-inflammatory effects of those samples were investigated on LPS-stimulated RAW264.7 cells and three animal models. The results showed that the anti-inflammatory effect of TTS in vitro was superior to the one of any other sample including 0% and 45% eluent, and total tanshinones capsules. In addition, TTS exhibited a stronger anti-inflammatory effect than that of dihydrotanshinone, tanshinone IIA, cryptotanshinone, and tanshinone I, respectively. For animal models, TTS could significantly suppress xylene-induced ear oedema and rescue LPS-induced septic death and acute kidney injury in mice. In summary, the separation process developed in the study was high-efficiency, economic, and low-contamination, which was fit to industrial producing. TTS is a potential agent for the treatment of inflammatory diseases.

Resveratrol protects against early polymicrobial sepsis-induced acute kidney injury through inhibiting endoplasmic reticulum stress-activated NF-κB pathway

Resveratrol, a polyphenol compound derived from various edible plants, protects against sepsis-induced acute kidney injury (AKI) via its anti-inflammatory activity, but the underlying mechanisms remain largely unknown. In this study, a rat model of sepsis was established by cecal ligation and puncture (CLP), 30 mg/kg resveratrol was intraperitoneally administrated immediately after the CLP operation. HK-2 cells treated by 1 μg/ml lipopolysaccharide, 0.2 μM tunicamycin, 2.5 mM irestatin 9389 and 20 μM resveratrol were used for in vitro study. The results demonstrated that resveratrol significantly improved the renal function and tubular epithelial cell injury and enhanced the survival rate of CLP-induced rat model of sepsis, which was accompanied by a substantial decrease of the serum content and renal mRNA expressions of TNF-α, IL-1β and IL-6. In addition, resveratrol obviously relieved the endoplasmic reticulum stress, inhibited the phosphorylation of inositol-requiring enzyme 1(IRE1) and nuclear factor-κB (NF-κB) in the kidney. In vitro studies showed that resveratrol enhanced the cell viability, reduced the phosphorylation of NF-κB and production of inflammatory factors in lipopolysaccharide and tunicamycin-induced HK-2 cells through inhibiting IRE1 activation. Taken together, administration of resveratrol as soon as possible after the onset of sepsis could protect against septic AKI mainly through inhibiting IRE1-NF-κB pathway-triggered inflammatory response in the kidney. Resveratrol might be a readily translatable option to improve the prognosis of sepsis.

Toxicity assessment of hydrogen peroxide on Toll-like receptor system, apoptosis, and mitochondrial respiration in piglets and IPEC-J2 cells

In this study, expressions of toll-like receptors (TLRs) and apoptosis-related genes in piglets and mitochondrial respiration in intestinal porcine epithelial cells were investigated after hydrogen peroxide (H₂O₂) exposure. The in vivo results showed that H₂O₂ influenced intestinal expressions of TLRs and apoptosis related genes. H₂O₂ treatment (5% and 10%) downregulated uncoupling protein 2 (UCP2) expression in the duodenum (P < 0.05), while low dosage of H2O2 significantly increased UCP2 expression in the jejunum (P < 0.05). In IPEC-J2 cells, H₂O₂ inhibited cell proliferation (P < 0.05) and caused mitochondrial dysfunction via reducing maximal respiration, spare respiratory, non-mitochondrial respiratory, and ATP production (P < 0.05). However, 50 uM H₂O₂ significantly enhanced mitochondrial proton leak (P < 0.05). In conclusion, H₂O₂ affected intestinal TLRs system, apoptosis related genes, and mitochondrial dysfunction in vivo and in vitro models. Meanwhile, low dosage of H₂O₂ might exhibit a feedback regulatory mechanism against oxidative injury via increasing UCP2 expression and mitochondrial proton leak.

Pterostilbene attenuates acute kidney injury in septic mice

Acute kidney injury (AKI) is a severe complication of sepsis with a high mortality and morbidity. Pterostilbene (Pte) has been suggested to confer anti-apoptotic and anti-inflammatory effects. In the current study, the effects of Pte on AKI were evaluated in septic mice. Cecal ligation and puncture surgery was performed to induce sepsis. The results suggested that Pte administration significantly decreased the levels of serum urea nitrogen and creatinine, and improved the survival rate of septic mice. Additionally, the renal injury induced by sepsis was attenuated by pterostilbene treatment. Notably, pterostilbene reduced Bcl-2-associated X protein expression, and levels of interleukin-1β and tumor necrosis factor-α, and upregulated B-cell lymphoma 2 expression. The results indicate that pterostilbene may serve as a potential therapeutic candidate for the treatment of AKI induced by sepsis.

Inducible overexpression of endothelial proNGF as a mouse model to study microvascular dysfunction

Impaired maturation of nerve growth factor precursor (proNGF) and its accumulation has been reported in several neurodegenerative diseases, myocardial infarction and diabetes. To elucidate the direct impact of proNGF accumulation identified the need to create a transgenic model that can express fully mutated cleavage-resistant proNGF. Using Cre-Lox technology, we developed an inducible endothelial-specific proNGF transgenic mouse (proNGF^Loxp) that overexpresses GFP-conjugated cleavage-resistant proNGF123 when crossed with VE-cadherin-CreERT2 (Cre). Expression of proNGF, inflammatory mediators, NGF and VEGF was evaluated by PCR, Western blot and immunohistochemistry. EC-proNGF overexpression was confirmed using colocalization of anti-proNGF within retinal vasculature. EC-proNGF did not cause retinal neurotoxicity or marked glial activation at 4-weeks. Microvascular preparation from Cre-proNGF mice showed significant imbalance of proNGF/NGF ratio, enhanced expression of TNF-α and p75^NTR, and tendency to impair TrkA phosphorylation compared to controls. EC-proNGF overexpression triggered mRNA expression of p75^NTR and inflammatory mediators in both retina and renal cortex compared to controls. EC-proNGF expression induced vascular permeability including breakdown of BRB and albuminuria in the kidney without affecting VEGF level at 4-weeks. Histopathological changes were assessed after 8-weeks and the results showed that EC-proNGF triggered formation of occluded (acellular) capillaries, hall mark of retinal ischemia. EC-proNGF resulted in glomerular enlargement and kidney fibrosis, hall mark of renal dysfunction. We have successfully created an inducible mouse model that can dissect the contribution of autocrine direct action of cleavage-resistant proNGF on systemic microvascular abnormalities in both retina and kidney, major targets for microvascular complication.

Resveratrol Does Not Protect from Ischemia-Induced Acute Kidney Injury in an in Vivo Rat Model

BACKGROUND/AIMS

The natural polyphenol resveratrol (RSV) has been shown to ameliorate ischemia/reperfusion (I/R)-induced damage. Therefore, a rat model of I/R-induced AKI equipped with intensive monitoring was utilized to examine direct renal protection by RSV in vivo.

METHODS

AKI was induced by bilateral renal clamping (45 min) followed by reperfusion (3 h). Solvent-free RSV was continuously infused intravenously (0.056 and 0.28 mg/kg) in a total volume of 7 ml/kg/h starting from 30 min before renal clamping. At a mean arterial blood pressure below 70 mmHg for more than 5 min, bolus injections of 0.5 ml 0.9% NaCl solution were administered repetitively (max. 5 ml/kg/h).

RESULTS

No differences could be found between normoxic control groups with/without RSV. Bilateral renal clamping and subsequent reperfusion caused a progressive rise in creatinine, cystatin C, and CK, a decrease in cellular ATP content and diuresis. Infusion of RSV increased sirtuin 1 expression after ischemia/reperfusion and was associated with decreased blood pressure during ischemia and early reperfusion accompanied by an increased requirement of bolus injections as well as with increased expression of TNFα.

CONCLUSION

RSV did not exert protective effects on I/R-induced AKI in the present short-term in vivo rat model. The lack of protection is potentially connected to aggravation of blood pressure instability.

Isoacteoside, a dihydroxyphenylethyl glycoside, exhibits anti-inflammatory effects through blocking toll-like receptor 4 dimerization

BACKGROUND AND PURPOSE

Isoacteoside (is a phenylethanoid isolated from Monochasma savatieri Franch. ex Maxim., which is an anti-inflammatory herb widely used in traditional Chinese medicine. However, the exact mechanism of the anti-inflammatory activity of isoacteoside is not completely understood. In this study, its anti-inflammatory mechanism was elucidated in mouse macrophages.

EXPERIMENTAL APPROACH

The expression of the NF-κB pathway, MAPK pathway, iNOS, TNF-α, IL-6 and IL-1β was evaluated using Western blotting, quantitative real-time PCR or ELISA. TLR4 dimerization was determined by transfecting HEK293T cells with TLR4 plasmids. The in vivo anti-inflammatory effect of isoacteoside was determined using mouse models of xylene-induced ear oedema, LPS-induced endotoxic shock and LPS-induced endotoxaemia-associated acute kidney injury (AKI).

KEY RESULTS

Isoacteoside suppressed COX-2, iNOS, TNF-α, IL-6 and IL-1β expression. Furthermore, isoacteoside attenuated the LPS-induced transcriptional activity of NF-κB by decreasing the levels of phosphorylated IκB-α and IKK and NF-κB/p65 nuclear translocation. In addition, isoacteoside inhibited LPS-induced transcriptional activity of AP-1 by reducing the levels of phosphorylated JNK1/2 and p38MAPK. Isoacteoside blocked LPS-induced TLR4 dimerization, resulting in a reduction in the recruitment of MyD88 and TIR-domain-containing adapter-inducing interferon-β (TRIF) and the phosphorylation of TGF-β-activated kinase-1 (TAK1). Pretreatment of mice with isoacteoside effectively inhibited xylene-induced ear oedema and LPS-induced endotoxic death and protected against LPS-induced AKI.

CONCLUSIONS AND IMPLICATIONS

Isoacteoside blocked TLR4 dimerization, which activates the MyD88-TAK1-NF-κB/MAPK signalling cascades and TRIF pathway. Our data indicate that isoacteoside is a potential lead compound for the treatment of inflammatory diseases.

Advanced glycation end products and lipopolysaccharides stimulate interleukin-6 secretion via the RAGE/TLR4-NF-κB-ROS pathways and resveratrol attenuates these inflammatory responses in mouse macrophages

Macrophages are essential for regulating the physiology of pregnancy; however, excessive inflammatory responses to macrophages, induced by infection and/or endogenous danger signals, may potentially result in complications during pregnancy. Advanced glycation end-products (AGE) and lipopolysaccharides (LPS) are known to induce inflammation and are associated with adverse developmental outcomes. The aim of the present study was to examine the effect of AGE and LPS on cytokines in the J774 murine macrophage cell line and the potential effect of resveratrol on AGE- and LPS-induced inflammation in macrophages. AGE and LPS significantly increased IL-6 mRNA expression and secretion in J774 macrophages (P<0.05). Although AGE and LPS significantly stimulated IL-1β mRNA expression (P<0.05), they had no significant effect on IL-1β secretion. To assess the receptors for AGE and LPS, including receptor for AGE (RAGE) and Toll-like receptor (TLR4), blocking reagents (RAGE antagonist or TLR4 inhibitor) were added to the J774 macrophages. IL-6 secretion induced by AGE or LPS was significantly inhibited by pretreatment with RAGE antagonist (P<0.05) or TLR4 inhibitor (P<0.05). IL-6 secretion was dependent on nuclear factor (NF)-κB activation and the production of reactive oxygen species (ROS; P<0.05). Resveratrol suppressed mRNA expression and intracellular IL-6 production, resulting in significantly decreased IL-6 secretion after treatment with LPS or AGE (P<0.01). Furthermore, treatment with Ex527, which is a sirtuin-1 (SIRT1) inhibitor, significantly attenuated the anti-inflammatory effect of resveratrol (P<0.05), and treatment with 5-aminoimidazole-4-carboxamide ribonucleotide, which is a 5' adenosine monophosphate-activated protein kinase (AMPK) activator, resulted in a significant decrease in IL-6 secretion in J774 macrophages (P<0.05). The results of the present study indicated that AGE and LPS increase IL-6 secretion depending on NF-κB activation and ROS production through RAGE and/or TLR4 in the J774 murine macrophage cell line. Based on the present study, resveratrol appears to be an effective regulator of the inflammatory responses associated with SIRT1 and AMPK activation in macrophages. These results suggest that resveratrol may have therapeutic applications for controlling immune responses during pregnancy.

Ginkgetin aglycone ameliorates LPS-induced acute kidney injury by activating SIRT1 via inhibiting the NF-κB signaling pathway

Background

Ginkgetin aglycone (GA), a novel Ginkgo biloba extract (GBE) by acid hydrolysis and recrystallization, is characterized by higher liposolubility and antioxidation than classical GBEs. There is no study depicting the functional role of GA in acute kidney injury (AKI). Here, we firstly reported the protective effect of GA on lipopolysaccharide (LPS)-induced AKI and its underlying mechanism.

Methods

ELISA analysis was applied to measure plasma level of TNF-α and IL-6, and NF-κB activity in kidney homogenate. Renal function analysis was performed by detecting serum concentration of Kim-1 and urine level of BUN. Cell apoptosis in kidney tissues was detected by TUNEL assay and caspase-3 activity assay. qRT-PCR was conducted to determine mRNA expression of TNF-α, IL-6 and IκBα. Western blot was carried out to confirm expression of p-IκBα, SIRT1, and iNOS.

Results

GA administration protected mice from LPS-induced AKI by attenuating inflammatory response, renal injury, as well as tubular apoptosis both in vivo. GA suppressed inflammatory response induced by LPS in HK-2 cells. Moreover, GA upregulated SIRT1 expression and blocked the NF-κB signaling pathway in LPS-induced AKT in vivo and vitro. Furthermore, suppression of SIRT1 abated the inhibitory effect of GA on LPS-induced inflammatory response and renal injury.

Conclusions

GA prevented LPS-induced AKI by activating SIRT1 via inhibiting the NF-κB signaling pathway, providing new insights into the function and molecular mechanism of GA in AKI. Therefore, GA may be a promising therapeutic agent for the treatment of septic AKI.

Total tanshinones exhibits anti-inflammatory effects through blocking TLR4 dimerization via the MyD88 pathway

Tanshinones belong to a group of lipophilic constituents of Salvia miltiorrhiza Bunge (Danshen), which is widely used in traditional Chinese medicine. A deluge of studies demonstrated that tanshinones exert anti-inflammatory effects, but the underlying mechanisms remain unclear to date. This study investigated the anti-inflammatory effects and mechanisms of total tanshinones (TTN). TTN suppressed the expression of cyclooxygenase-2 (COX-2) and inducible nitric oxide synthase (iNOS) and the secretion of TNF-α, IL-6, and IL-1β in RAW264.7 cells, bone marrow-derived macrophages, and THP-1 cells. TTN attenuated the LPS-induced transcriptional activity of NF-κB and decreased IκB-α and IKK phosphorylation and NF-κB/p65 nuclear translocation. Furthermore, TTN inhibited the LPS-induced transcriptional activity of AP-1, which was induced by the reduction of JNK1/2, ERK1/2, and p38MAPK phosphorylation. TTN blocked LPS-induced Toll-like receptor 4 (TLR4) dimerization, which consequently decreased MyD88 recruitment and TAK1 phosphorylation. In addition, TTN pretreatment effectively inhibited xylene-induced ear edema and LPS-induced septic death and improved LPS-induced acute kidney injury in mice. TTN exerts anti-inflammatory effects in vitro and in vivo by blocking TLR4 dimerization to activate MyD88–TAK1–NF-κB/MAPK signaling cascades, which provide the molecular basis of the anti-inflammatory effect of Danshen and suggest that TTN is a potential agent for the treatment of inflammatory diseases.

Naturally Occurring Compounds: New Potential Weapons against Oxidative Stress in Chronic Kidney Disease

Oxidative stress is a well-described imbalance between the production of reactive oxygen species (ROS) and the antioxidant defense system of cells and tissues. The overproduction of free radicals damages all components of the cell (proteins, lipids, nucleic acids) and modifies their physiological functions. As widely described, this condition is a biochemical hallmark of chronic kidney disease (CKD) and may dramatically influence the progression of renal impairment and the onset/development of major systemic comorbidities including cardiovascular diseases. This state is exacerbated by exposure of the body to uremic toxins and dialysis, a treatment that, although necessary to ensure patients' survival, exposes cells to non-physiological contact with extracorporeal circuits and membranes with consequent mitochondrial and anti-redox cellular system alterations. Therefore, it is undeniable that counteracting oxidative stress machinery is a major pharmacological target in medicine/nephrology. As a consequence, in recent years several new naturally occurring compounds, administered alone or integrated with classical therapies and an appropriate lifestyle, have been proposed as therapeutic tools for CKD patients. In this paper, we reviewed the recent literature regarding the "pioneering" in vivo testing of these agents and their inclusion in small clinical trials performed in patients affected by CKD.

Resveratrol enhances vascular reactivity in mice following lipopolysaccharide challenge via the RhoA-ROCK-MLCP pathway

The aim of the present study was to identify whether sepsis-induced vascular hyporeactivity is associated with microcirculation disturbance and multiple organ injuries. The current study assessed the impact of resveratrol (Res) treatment on lipopolysaccharide (LPS) challenge mediated vascular hyporeactivity. Effects of Res treatment (30 mg/kg; i.m.) at 1 h following LPS stimulation (5 mg/kg; i.v.) on the survival time, mean arterial pressure (MAP), and maximal difference of MAP (ΔMAP) to norepinephrine (NE; 4.2 µg/kg) in mice were observed. The reactivity to gradient NE of isolated mesenteric arterioles and the association with the RhoA-RhoA kinase (ROCK)-myosin light chain phosphatase (MLCP) pathway were investigated by myography, and the signaling molecule protein levels were assessed using ELISA. Res treatment prolonged the survival time of mice subjected to LPS challenge, but did not prevent the LPS-induced hypotension and increase in ΔMAP. Res treatment and RhoA agonist U-46619 incubation prevented LPS-induced vascular hyporeactivity ex vivo, which were suppressed by incubation with ROCK inhibitor Y-27632. LPS-induced vascular hyporeactivity was not affected by the MLCP inhibitor okadaic acid incubation, but was further downregulated by the co-incubation of OA plus Y-27632. The inhibiting effect of Y-27632 on Res treatment was eradicated by incubation with U-46619. Furthermore, RhoA inhibitor C3 transferase did not significantly inhibit the enhancing role of Res treatment, which was further increased by U-46619 plus C3 transferase co-incubation. In addition, Res treatment eradicated the LPS-induced decreases in p-RhoA and p-Mypt1 levels and increases in MLCP levels. The results of the present study indicate that post-treatment of Res significantly ameliorates LPS-induced vascular hyporeactivity, which is associated with the activation of the RhoA-ROCK-MLCP pathway.

Mitochondria Damage and Kidney Disease

The kidney is a vital organ that demands an extraordinary amount of energy to actively maintain the body's metabolism, plasma hemodynamics, electrolytes and water homeostasis, nutrients reabsorption, and hormone secretion. Kidney is only second to the heart in mitochondrial count and oxygen consumption. As such, the health and status of the energy power house, the mitochondria, is pivotal to the health and proper function of the kidney. Mitochondria are heterogeneous and highly dynamic organelles and their functions are subject to complex regulations through modulation of its biogenesis, bioenergetics, dynamics and clearance within cell. Kidney diseases, either acute kidney injury (AKI) or chronic kidney disease (CKD), are important clinical issues and global public health concerns with high mortality rate and socioeconomic burden due to lack of effective therapeutic strategies to cure or retard the progression of the diseases. Mitochondria-targeted therapeutics has become a major focus for modern research with the belief that maintaining mitochondria homeostasis can prevent kidney pathogenesis and disease progression. A better understanding of the cellular and molecular events that govern mitochondria functions in health and disease will potentially lead to improved therapeutics development.

Ratiometric Two-Photon Fluorescent Probe for in Vivo Hydrogen Polysulfides Detection and Imaging during Lipopolysaccharide-Induced Acute Organs Injury

Acute organ injury observed during sepsis, caused by an uncontrolled release of inflammatory mediators, such as lipopolysaccharide (LPS), is quite fatal. The development of efficient methods for early diagnosis of sepsis and LPS-induced acute organ injury in living systems is of great biomedical importance. In living systems, cystathionine γ-lyase (CSE) can be overexpressed due to LPS, and H₂S_n can be formed by CSE-mediated cysteine metabolism. Thus, acute organ injury during sepsis may be correlated with H₂S_n levels, making accurate detection of H₂S_n in living systems of great physiological and pathological significance. In this work, our previously reported fluorescent platform was employed to design and synthesize a FRET-based ratiometric two-photon (TP) fluorescent probe TPR-S, producing a large emission shift in the presence of H₂S_n. In this work, a naphthalene derivative two-photon fluorophore was chosen as the energy donor; a rhodol derivative fluorophore served as the acceptor. The 2-fluoro-5-nitrobenzoate group of probe TPR-S reacted with H₂S_n and was selectively removed to release the fluorophore, resulting in a fluorescent signal decrease at 448 nm and enhancement at 541 nm. The ratio value of the fluorescence intensity between 541 and 448 nm (I_541 nm/I_448 nm) varied from 0.13 to 8.12 (∼62-fold), with the H₂S_n concentration changing from 0 to 1 mM. The detection limit of the probe was 0.7 μM. Moreover, the probe was applied for imaging H₂S_n in living cells, tissues, and organs of LPS-induced acute organ injury, which demonstrated its practical application in complex biosystems as a potential method to achieve early diagnosis of LPS-induced acute organ injury.

Resveratrol, a natural antioxidant, protects monosodium iodoacetate-induced osteoarthritic pain in rats

BACKGROUND

Osteoarthritis (OA) is a chronic progressive joint disease characterized by advanced joint pain, subchondral bone sclerosis and articular cartilage degeneration. Resveratrol has been shown to have anti-inflammatory, cardioprotective and antioxidant properties and to inhibit platelet aggregation and coagulation. However, the effects of resveratrol on OA have not been examined. In this study, we investigate the protective effects of resveratrol on monosodium iodoacetate (MIA)-induced OA through inhibition of cyclooxygenase (COX-2) and inducible nitric oxide synthase (iNOS) signaling pathway in a rat model.

METHODS

A single intra-articular injection of MIA was injected into rats for the induction of OA. The mechanical, heat and cold hyperalgesia were measured at days 0, 7 and 14. The serum and synovial fluid levels of IL-1β, IL-10 and TNF-α and osteocalcin were measured by enzyme-linked immunosorbent assay. The mRNA and protein expressions of IL-1β, IL-10, TNF-α, Il-6, MMP-13 and COX-2 and iNOS were determined by RT-PCR and western blot, respectively. Osteoarthritic lesion in the knee joint was evaluated by histological analysis.

RESULTS

MIA-injected rats treated with resveratrol at a dose of either 5 or 10mg/kg body weight were significantly reduced hyperalgesia of mechanical, heat and cold and increased the vertical and horizontal movements. Subsequently, MIA-injected rats increased serum and synovial fluid levels of IL-1β, IL-10, IL-6, TNF-α, MMP-13 and osteoclastic activity marker, osteocalcin and its articular cartilage mRNA and protein expressions. Further, MIA-injected rats increased COX-2 and iNOS mRNA and protein expressions were decreased by resveratrol. The protective effect of resveratrol was comparable to a reference drug, etoricoxib. The cartilage damage induced by MIA were attenuated by resveratrol.

CONCLUSIONS

Taken together, resveratrol has the potential to improve MIA-induced cartilage damage by inhibiting the levels and expressions of inflammatory mediators suggesting that resveratrol may be a potential therapeutic agent for OA.

The neutrophil elastase inhibitor, sivelestat, attenuates sepsis-related kidney injury in rats

Sepsis-induced acute kidney injury (AKI) represents a major cause of mortality in intensive care units. Sivelestat, a selective inhibitor of neutrophil elastase (NE), can attenuate sepsis-related acute lung injury. However, whether sivelestat can preserve kidney function during sepsis remains unclear. In this study, we thus examined the effects of sivelestat on sepsis-related AKI. Cecal ligation and puncture (CLP) was performed to induce multiple bacterial infection in male Sprague-Dawley rats, and subsequently, 50 or 100 mg/kg sivelestat were administered by intraperitoneal injection immediately after the surgical procedure. In the untreated rats with sepsis, the mean arterial pressure (MAP) and glomerular filtration rate (GFR) were decreased, whereas serum blood urea nitrogen (BUN) and neutrophil gelatinase-associated lipocalin (NGAL) levels were increased. We found that sivelestat promoted the survival of the rats with sepsis, restored the impairment of MAP and GFR, and inhibited the increased BUN and NGAL levels; specifically, the higher dose was more effective. In addition, sivelestat suppressed the CLP-induced macrophage infiltration, the overproduction of pro-inflammatory mediators (tumor necrosis factor-α, interleukin-1β, high-mobility group box 1 and inducible nitric oxide synthase) and serine/threonine kinase (Akt) pathway activation in the rats. Collectively, our data suggest that the inhibition of NE activity with the inhibitor, sivelestat, is beneficial in ameliorating sepsis-related kidney injury.

Bridging translation for acute kidney injury with better preclinical modeling of human disease

The current lack of effective therapeutics for patients with acute kidney injury (AKI) represents an important and unmet medical need. Given the importance of the clinical problem, it is time for us to take a few steps back and reexamine current practices. The focus of this review is to explore the extent to which failure of therapeutic translation from animal studies to human studies stems from deficiencies in the preclinical models of AKI. We will evaluate whether the preclinical models of AKI that are commonly used recapitulate the known pathophysiologies of AKI that are being modeled in humans, focusing on four common scenarios that are studied in clinical therapeutic intervention trials: cardiac surgery-induced AKI; contrast-induced AKI; cisplatin-induced AKI; and sepsis associated AKI. Based on our observations, we have identified a number of common limitations in current preclinical modeling of AKI that could be addressed. In the long term, we suggest that progress in developing better preclinical models of AKI will depend on developing a better understanding of human AKI. To this this end, we suggest that there is a need to develop greater in-depth molecular analyses of kidney biopsy tissues coupled with improved clinical and molecular classification of patients with AKI.

Effects of resveratrol and genistein on nuclear factor‑κB, tumor necrosis factor‑α and matrix metalloproteinase‑9 in patients with chronic obstructive pulmonary disease

Chronic airway inflammation and airway remodeling are the major pathophysiological characteristics of chronic obstructive pulmonary disease (COPD). Resveratrol and genistein have been previously demonstrated to have anti‑inflammatory and antioxidative properties. The present study aimed to measure the inhibitory effects of resveratrol and genistein on tumor necrosis factor (TNF)‑α and matrix metalloproteinase (MMP)‑9 concentration in patients with COPD. Lymphocytes were isolated from the blood of 34 patients with COPD and 30 healthy subjects, then randomly divided into the following four treatment groups: Control, dexamethasone (0.5 µmol/l), resveratrol (12.5 µmol/l) and genistein (25 µmol/l) groups. After 1 h of treatment, 100 µl lymphocytes were collected for nuclear factor (NF)‑κB immunocytochemical staining. After 48 h treatment, the supernatant of the lymphocytes was collected for analysis of TNF‑α and MMP‑9 concentration levels. The percentage of lymphocytes with positive nuclear NF‑κB expression was analyzed by immunocytochemical staining. The concentration levels of TNF‑α and MMP‑9 were measured using radioimmunoassay and enzyme‑linked immunosorbent assay, respectively. The present study demonstrated that the percentage of NF‑κB‑positive cells, and the levels of TNF‑α and MMP‑9 in lymphocytes from patients with COPD patients were significantly higher compared with healthy subjects. Additionally, there were positive correlations between the percentage of NF‑κB‑positive cells, and the concentration levels of TNF‑α and MMP‑9 in patients with COPD. All three factors were significantly reduced in lymphocytes treated with resveratrol and genistein, and the inhibitory effects of resveratrol on NF‑κB, TNF‑α and MMP‑9 were more potent than the effects of genistein. In conclusion, resveratrol and genistein may inhibit the NF‑κB, TNF‑α and MMP‑9‑associated pathways in patients with COPD. It is suggested that resveratrol and genistein may be potential drugs candidates for use in the treatment of COPD.